KO-5 was a shore based device located at major communications stations. Originally built for the US Army to encrypt facsimile in the early 1950's and later adapted to encrypt 16 channels of 100 WPM teletype circuits simultaneously. It was tube type machine about 20 feet long, using magnetic core memory, pre-punched paper key tape to load the key, Morse code communications for starting and synchronizing, and commonly called 'The Horse" by US Navy personnel. It's 16 teletype channels were multiplexed with the aid of an FGC-60 tone converter. It was used primarily for long distance high frequency full duplex communications.Contributor: Art Richie
May 29/02